An Examination of the Performance and Physiological Demands of High-Performance Mixed Teams Relay Triathlon.

  • Robert Palmer

Student thesis: Doctoral Thesis


Triathlon is a multi-disciplinary sport that requires the sequential completion of a swim, cycle, and run section. Currently, short distance triathlon events include the sprint distance triathlon (SDT; 750m swim, 20km bike, 5km run) and Olympic distance triathlon (ODT; 1.5km swim, 40km cycle, 10km run). The rapid increase in the popularity of triathlon worldwide has led to the inclusion of the mixed team relay (MTR) (1F; 1M; 1F; 1M) event (4x 250-300m swim, 6-8km cycle, 1.6-2km run) at international level, including for the first time at the recent 2020 Tokyo Olympic Games.

The physiological basis for SDT and ODT success is complex for a number of reasons. Firstly, the mixed energy system requirements of the events. Secondly, the varying distances and exercise modes which need to be optimally linked together. Current research reports that the performance and physiological basis for triathlon success are unique but can be viewed as an endurance sport where an athlete’s ability to efficiently turn over high amounts of energy to produce and sustain a high-power output or velocity over a prolonged period is the strongest determinant of triathlon success. For example, research has suggested that SDT and ODT require sustained metabolic work intensities of ~65-80% of peak oxygen uptake. Furthermore, when blood lactate concentration ([BLa] and %HRmax measures are considered, SDT appears to be performed at a higher intensity than ODT, suggesting that there is an effect of distance on the performance and physiological demands of triathlon. However, it is yet to be determined what, for example, the % peak oxygen uptake, [BLa], and % heart rate (HR) max values are required during high performance MTR triathlon. Additionally, how % peak oxygen uptake, [BLa], and %HRmax during MTR compare to the same variables previously reported for ODT and SDT.

Through a series of three related manuscripts (Paper 1, Chapter 2; Study 1, Chapter 3; and Study 2, Chapter 4) the present thesis has three primary aims: 1) to systematically identify and critically discuss the current body of research literature examining performance, physiological, and pacing demands experienced during an ODT, SDT, and MTR triathlon; 2) to quantify the relative performance and physiological demands of a complete simulated MTR triathlon (sMTR), and compare this data to a relevant maximal swim, cycle, and run tests conducted in isolation; and 3) to investigate the effects of three specific warm-up (WU) protocols on sMTR performance (300m swim, 10.5min variable cycle, and 1.8km outdoor run). WUs included a moderate aerobic run-swim (WU1), a progressive high intensity intermittent (HII) swim-cycle (WU2), and a plyometric/circuit style dryland (WU3), in a group of high performance and elite triathletes.

Following the Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines (PRIMSA) Paper 1 (Chapter 2) revealed 21 papers that met the inclusion criteria, and three main areas of previous research. These included the performance and physiological demands, pacing strategies, and the effect of the previous discipline or section during SDT or ODT. The first major finding from the review was that no research has examined or reported on MTR triathlon in any of the main areas of research. Secondly, that there appears to be a clear effect of triathlon distance on the performance and physiological demands, pacing strategies, and the effect of the previous discipline or section during ODT or SDT. The available research strongly suggests based on high %HRmax and [BLa] measures that both ODT and SDT are completed at sustained high intensities. Furthermore, that the shorter distance SDT is completed at a higher sustained intensity compared to ODT. The review also identified that a fast swim start during both ODT and SDT with a purposeful reduction in speed towards the end of the swim section may result in favorable swim performance. In addition, both efficiently drafting and an even or slightly negative pacing (a gradual increase in race velocity is observed during the event; i.e., a slower start) pattern may improve cycle and subsequent run performance during both ODT and SDT. At present, it appears that elite triathletes currently adopt a positive run pace during races. However, a slightly negative run pace with a concomitant end-spurt may be best for both run and overall ODT or SDT performance. Finally, the review revealed the effect of the previous discipline on subsequent performance seems to be strongly related to how the triathlete paces each race section. Importantly, no research to date has examined any of the above factors in relation to the new Olympic sport of MTR triathlon.

Conducting a laboratory-controlled study working with high performance triathletes and examining the performance and physiological demands of the swim, cycle, and run sections during a sMTR, Study 1 (Chapter 2) revealed that triathletes sustain near maximal intensities for both the duration of each sMTR section and the entire sMTR (250m swim; 8km cycle; 2km run). Firstly, sMTR swimming was performed at a sustained intensity of 95.3±2.1% of previously determined critical swim speed (CSS). sMTR mean swim speed was 1.4±0.1m.sec-1 and CSS speed was 1.5.±0.2m.sec-1. Secondly, sMTR cycling was performed at a sustained intensity of 100.9±6.1% of cycle power at ventilatory threshold (VT) and 83.1± 3.6% of maximal power at previously determined cycling VO2peak (peak oxygen uptake) with sMTR mean cycle power measured at 286.85±8.7W and 344.06±3.4W at VO2peak. Finally, sMTR running was performed at a sustained intensity of 96.9±3.9% of run pace at VT and 92.0±4.4% of run pace at VO2peak. sMTR mean run pace was 3:39.9± and pace at VO2peak was 3:21.3± during the previously-completed maximal running test. In summary, the available data from Study 1 strongly suggests that both the sMTR and each section of the event is performed at a higher sustained intensity than previously observed for both SDT and ODT. Therefore, given the high relative intensity of sMTR triathlon, triathletes may require a specific pre-race warm-up to be better able to meet the demands of MTR triathlon.

Using a randomised counterbalanced-crossover design, Study 2 (Chapter 4) revealed that performing a progressive anerobic HII swim-cycle WU (WU2) is best to improve sMTR cycle tolerance, run, and overall MTR performance compared to a moderate aerobic WU (WU1) and a plyometric/circuit style dryland WU (WU3). in high performance and elite triathletes. The major findings were firstly, that overall sMTR performance was significantly improved following WU2 (1174.8±59.2sec; SE=24.2) compared to WU1 (1189.2±66.1sec; SE=27.0) and WU3 (1191.8±66.1sec; SE=27.0). Secondly, 2km run performance was significantly faster following WU2 (336.3sec) compared to WU1 (350.4sec) and WU3 (350.5sec). Finally, [BLa] was significantly lower pre-run (post-cycle) following WU2 (7.7±1.9mmo.L-1) compared to WU1 (11.6 ± 2.7mmol.L-1) and WU3 (11.1 ± 2.8mmol.L-1). Taken together, these results demonstrate that that the run performance was the primary performance difference between the three WU conditions as evidenced by the significantly better mean sMTR run time and mean lap one run pace following the WU2 condition. Importantly, this may have been the result of the cycle (power matched across conditions) during WU2 having been better tolerated physiologically as evidenced by the significantly lower [BLa] following the sMTR cycle section after completing WU2. Therefore, due to the fast start and high intensity nature of MTR racing a HII swim-cycle WU may be an important part of MTR race day preparation in elite and high-performance triathletes.

Taken together, the present thesis is the first to examine in detail performance, physiological, and pacing factors related to MTR. The thesis and associated papers are the first to examine in detail these key factors relating to MTR performance. The results have clearly demonstrated that there is a significant effect of race distance when the performance, physiological, and pacing demands are compared between ODT, SDT, and MTR. Moreover, the findings of Study 1 highlighted that MTR is performed at near maximal intensities for swim cycle and run sections when expressed as a percentage of relevant individual maximal tests. Finally, Study 2 revealed that MTR performance may be improved by a specific HII swim-cycle WU on race day. The information presented in this thesis will inform and assist coaches, sport scientists, and triathletes of the specific performance, physiological, and pacing demands required to effectively and validly design and structure training plans to meet the specific demands of MTR competition.
Date of Award2022
Original languageEnglish
SupervisorPeter Reaburn (Supervisor), Annette Eastwood (Supervisor) & Vernon Coffey (Supervisor)

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